The purpose of this study is to estimate, correlate, and compare the incidence of acute rectal, bladder and other acute toxicities between 3-D CRT and IMRT in prostate cancer patients treated with post-operative radiation therapy, to quantify, compare, and correlate the dose volume histogram (DVH) doses (e.g., Vmean, Vmedian, V25, V50, V75) to the surrounding critical organs (i.e., rectum and bladder) between 3-D CRT and IMRT, and to measure, compare, and correlate the quality of life scores of participants using the EORTC Quality of Live Questionnaires (QLQ), called "QLQ-C30" and "EPIC-26". These survey instruments will measure quality of life differences during the study; the comparison will be done between 3-D CRT and IMRT treatment arms.